The invention relates to a torsional vibration damper, especially for a clutch disc of a motor vehicle friction clutch.
From West German Patent Application No. 3,415,927 a torsional vibration damper for the clutch disc of a motor vehicle friction clutch is known the hub of which carries a hub disc provided with an external toothing. The hub disc forms a first disc part which is limitedly rotatably enclosed concentrically by an annular second disc part. The second disc part has an internal toothing which engages with play in rotation in the external toothing of the first disc part. Two firmly interconnected cover or side discs are arranged on mutually axially opposite sides of the disc parts, rotatably in relation thereto. The side discs are coupled through first springs with the second disc part and form an under-load vibration damper. In a recess defined by two teeth of the second disc part there is seated a second spring which is seated in the circumferential direction in apertures of a substantially U-shaped stirrup-type spring retaining fitting. The spring retaining fitting in turn is seated in a recess which is formed by two teeth of the external toothing of the first disc part. The second spring seated in the spring retaining fitting is a component of an idling vibration damper.
The conventional spring retaining fitting has a form which is comparatively expensive to produce. Furthermore assembly can lead to problems, especially if the spring retaining fitting is to be used at the same time for the axial fixing of the second spring.
The invention aims at improving a torsional vibration damper of the kind as known from German Patent Application No. 3,415,927 so that the advantages achieved by the spring retaining fitting are retained but the production and assembly are facilitated.